1. Field of the Invention
The present invention relates to a mobile hoist for enabling a user to lift relatively heavy loads. More particularly, the present invention is directed to a movable hoist having a base provided with casters, a vertical beam supported by the base, and a horizontal boom having a pulley and cable system supported by the vertical beam.
2. Description of the Related Art
In the construction industry, it is often necessary for workers to manipulate heavy and/or large sized objects such as drywall panels, girder beams, wood beams, logs, etc. It may be necessary for workers to move and/or lift such objects, for example, when installing the object in place or when moving the object to a higher story. Large cranes, used in large scale construction projects, could be used to perform such tasks. However, such large cranes are prohibitively expensive for small scale construction projects, and could not be used when a roof or other building structure covers the location at which the manipulation of the heavy and/or oversized object is to take place.
Therefore, the present invention which allows workers to easily manipulate heavy and/or oversize objects, would be very useful in the construction industry. In addition, the load lifting apparatus of the present invention will be generally useful for manipulating heavy and/or oversize objects and thus will have a myriad of different applications. For example, the load lifting apparatus of the present invention would be useful in stacking objects in a warehouse type environment. Although mobile hoists are known in the related art none are seen to have the unique structure, the ease of fabrication, and the simplicity of the present invention.
U.S. Pat. No. 4,236,859, issued to Richard A. Stearn et al. on Dec. 2, 1980, shows a mobile hoist with a frame that straddles the object to be lifted. Pairs of straps cradle the object to be lifted. Each pair of straps is supported by a pulley system on either side of the frame structure. The pulley systems are used to lift the ends of the straps, thus lifting the object cradled by the straps. Stearn et al. does not show the tricycle type base or the translatable horizontal boom of the present invention.
U.S. Pat. No. 4,239,443, issued to Ambrose L. Rysewyk on Dec. 16, 1980, shows a mobile hoist for loading and unloading articles onto and from shelves. The Rysewyk device has a fixed length vertical beam. The horizontal boom rides up and down in tracks provided in the vertical beam. Rysewyk does not show the tricycle type base, the height adjustable vertical beam, or the translatable horizontal boom with a pulley at each end as used in the present invention.
U.S. Pat. No. 5,297,832, issued to Fred Dewey et al. on Mar. 29, 1994, shows an apparatus for lifting bundles of logs from the bed of a truck. Dewey et al. does not show the tricycle type base, the height adjustable vertical beam, or the translatable horizontal boom with a pulley at each end as used in the present invention.
U.S. Pat. No. 5,340,085, issued to Howard M. Keibler on Aug. 23, 1994, shows an apparatus for allowing one person to lift heavy logs. Keibler does not show the tricycle type base, the height adjustable vertical beam, or the translatable horizontal boom with a pulley at each end as used in the present invention.
U.S. Pat. No. 5,456,299, issued to Denis Kusek et al. on Oct. 10, 1995, shows a mobile log cutting apparatus. Kusek et al. does not show the tricycle type base, the height adjustable vertical beam, or the translatable horizontal boom with a pulley at each end as used in the present invention.
Soviet inventor's certificate 1669849, dated Aug. 15, 1991, shows an apparatus for lifting slabs. Soviet document '849 does not show the tricycle type base, the height adjustable vertical beam, or the translatable horizontal boom with a pulley at each end as used in the present invention.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.